(a) Field of the Invention
The present invention relates to a thin film transistor array substrate and, more particularly, to a thin film transistor array substrate having a structure for laser repair.
(b) Description of the Related Art
Generally, a thin film transistor array substrate is used as a circuit substrate for independently driving the respective pixels in a liquid crystal display or an organic electro luminescence display. The thin film transistor array substrate typically has gate lines for transmitting scanning signals, data lines for transmitting image signals, thin film transistors connected to the gate lines and the data lines, pixel electrodes connected to the thin film transistors, a gate insulating layer covering the gate lines, and a passivation layer covering the thin film transistors and the data lines. Each thin film transistor includes a gate electrode connected to the gate line, a channel-forming semiconductor layer, a source electrode connected to the data line, a drain electrode connected to the pixel electrode, a gate insulating layer, and a passivation layer. The thin film transistor functions as a switching circuit where the image signal from the data line is transmitted to the pixel electrode in accordance with the scanning signal from the gate line.
In the thin film transistor array substrate, as each signal line is connected to each pixel column or each pixel row, each pixel has a thin film transistor, the respective line should be formed with a minute size of several micrometers or less. Therefore, in the process of fabricating the thin film transistor array substrate, there always exists a possibility of device failure due to a short or an open in the line. For this reason, a repair structure such as a repair ring is usually provided to the thin film transistor array substrate for repairing device failure. In a case of device failure, a failure line in the device is cut using a laser, or a repair structure is connected to the failure line.
Generally, repair of a device failure is preformed during a module fabrication process. For instance, in the case of a liquid crystal display, a thin film transistor array substrate is combined with a color filter substrate, and a liquid crystal is injected between the thin film transistor array substrate and the color filter substrate. Thereafter, the repair is preformed on the side of the thin film transistor array substrate not having a line assembly. That is, laser is illuminated through a rear surface of the thin film transistor array substrate to short(connect) or cut failure lines placed at the front surface thereof. This type of repair frequently fails to get desired result because an exact laser illumination location may not be easily found. Particularly, as a transparent conductive line based on indium tin oxide (ITO) or indium zinc oxide (IZO) is not easily discriminated through the rear surface of the thin film transistor array substrate, activation of a laser may illuminate unintended overlapping areas of the transparent conductive line with other lines, thereby the desired repair is not properly performed. Accordingly, a need exists for a thin film transistor array panel having a laser illumination indicator for easily and correctly repairing a device failure.
A thin film transistor array substrate is provided, which includes: an insulating substrate; a plurality of wiring lines formed on the insulating substrate; and a plurality of indicators formed on the plurality of wiring lines for indicating locations for laser illumination repair.
According to an embodiment of the present invention, the plurality of indicators are formed in the shape of protrusions or grooves. The plurality of wiring lines include a storage electrode line and a plurality of storage electrodes branched from the storage electrode. The plurality of indicators include at least two indicators separately formed on the storage electrode line and the plurality of storage electrodes. Preferably, each indicator has a length of about 4 xcexcm to about 5 xcexcm and a width of about 0.5 xcexcm to about 1.5 xcexcm.
A thin film transistor array substrate is also provided, which includes: a transparent insulating substrate; a first signal line formed on the insulating substrate; a second signal line formed on the insulating substrate, the second signal line crossing over the first signal line while being insulated from the first signal line; a signal line assembly including a base line and a plurality of branch lines branched from the base line, the base line crossing over the second signal line while being insulated from the second signal line; a bridge interconnecting parts of the signal line assembly placed at both sides of the first signal line while being insulated from the first signal line; a thin film transistor connected to the first and the second signal lines; and a pixel electrode connected to the thin film transistor, wherein the signal line assembly includes a plurality of indicators for indicating locations of laser illumination during repairing line failures at the first signal line or the second signal line.
According to an embodiment of the present invention, the plurality of indicators are formed in the shape of protrusions or grooves. The plurality of indicators include at least two indicators separately formed on the base line and the plurality of branch lines. Preferably, each indicator has a length of about 4 xcexcm to about 5 xcexcm and a width of about 0.5 xcexcm to about 1.5 xcexcm.
A thin film transistor array substrate is also provided, which includes: an insulating substrate; a gate line assembly formed on the insulating substrate, the gate line assembly including a gate line extending in the horizontal direction and a gate electrode connected to the gate line; a storage electrode line assembly formed on the insulating substrate, the storage electrode line assembly including a storage electrode line extending parallel to the gate line, and a plurality of storage electrodes branched from the storage electrode line while extending in the vertical direction; a gate insulating layer covering the gate line assembly and the storage electrode line assembly; a semiconductor layer formed on the gate insulating layer while being partially overlapped with the gate electrode; a data line assembly including a data line formed on the gate insulating layer while extending in the vertical direction, a source electrode connected to the data line while being partially placed over the semiconductor layer, and a drain electrode facing the source electrode while being partially placed over the semiconductor layer; a passivation layer covering the data line assembly and the semiconductor layer having a first contact hole exposing the drain electrode, a second contact hole exposing the storage electrode, and a third contact hole exposing the storage electrode line; a pixel electrode formed on the passivation layer while being connected to the drain electrode through the first contact hole; and a bridge formed on the passivation layer while interconnecting the storage electrode and the storage electrode line placed at both sides of the gate line through the second and the third contact holes, wherein the plurality of storage electrodes and the storage electrode line include a plurality of indicators placed close to the second and the third contact holes for indicating locations of laser illumination for repairing line failures.
According to an embodiment of the present invention, the thin film transistor array substrate further includes a data metallic piece overlapped with the bridge and the gate line, the data metallic piece being connected to the bridge through fourth contact hole of the passivation layer. The plurality of indicators include at least two indicators separately formed on the storage electrode line and the plurality of storage electrodes. The plurality of indicators are located adjacent to the pixel electrode and the bridge.
A thin film transistor array substrate is also provided, which includes: an insulating substrate; a gate line assembly formed on the insulating substrate, the gate line assembly having a gate line extending in the horizontal direction, and a gate electrode connected to the gate line; a storage electrode line assembly formed on the insulating substrate, the storage electrode line assembly including a storage electrode line extending parallel to the gate line, and a plurality of storage electrodes branched from the storage electrode line while extending in the vertical direction; a gate insulating layer covering the gate line assembly and the storage electrode line assembly; a semiconductor layer formed on the gate insulating layer while being partially overlapped with the gate electrode; a data line assembly including a data line formed on the gate insulating layer while extending in the vertical direction, a source electrode connected to the data line while being partially placed over the semiconductor layer, and a drain electrode partially placed on the semiconductor layer while facing the source electrode; a passivation layer covering the data line assembly and the semiconductor layer, the passivation layer having first contact hole exposing the drain electrode, second contact hole exposing the storage electrode, and third contact hole exposing the storage electrode line; a pixel electrode formed on the passivation layer, the pixel electrode being connected to the drain electrode through the first contact hole; and a bridge formed on the passivation layer while interconnecting the storage electrode and the storage electrode line placed at both sides of the gate line through the second and third contact holes; wherein a plurality of indicators are provided between the portions of the storage electrode line and the storage electrode overlapped with the bridge, and the portion of the storage electrode line and the storage electrode overlapped with the pixel electrode.